- The U.S. Chamber of Commerce has taken the rare step of endorsing the Democratic incumbent in one of California's most hotly contested congressional races.

The trade group overwhelmingly endorses Republican candidates. But this time it sided with Rep. Scott Peters, a freshman representing a San Diego-based district. Of the more than 260 candidates the chamber has endorsed this election cycle, Peters is only the fourth Democrat.

On Wednesday, Peters' campaign released an endorsement letter from Thomas Donahue, the group's president and chief executive.

"We believe that your re-election to the U.S. House of Representatives will help produce sustained economic growth, help create jobs, and get our country back on track," Donahue wrote.

The endorsement is a coup for Peters, who faces a strong challenge from Republican Carl DeMaio, a former member of the San Diego City Council who also started and sold two businesses.